Crystalline resins in which crystals with regularly arranged molecular chains are present have many useful characteristics such as high mechanical strength and rigidity, and excellent chemical resistance. Such crystalline resins are easily processed, and therefore have been conventionally widely used mainly for mechanism components and sliding components in precision equipment, home electronics, OA equipment, automobiles, industrial materials, miscellaneous goods, and the like.
Metallic color pigments made of metal particles, typified by scale-like aluminum powders (hereinafter, also referred to as “aluminum flake”), are compounded in various resins in order to impart a characteristic metallic gloss feeling called a metallic tone. Resin compositions to which such metallic color pigments are compounded are used for interior and exterior components for automobiles, personal computer casings, and the like.
Examples of such resin compositions which are known include the following resin compositions described in PTLs below, and for example, there have been made attempts to impart any design by molding of a resin having a glossy pigment for exhibition of metallic gloss properties. Specifically, JP1987020574A (PTL 1) and JP1986159453A (PTL 2) each have disclosed a molded article formed from a synthetic resin composition to which a specified metallic pigment is compounded. JP2010065210A (PTL 3) has proposed a polyacetal resin composition including a weathering agent, an aluminum particle having specified particle size, particle size distribution and particle thickness, and a specified fatty acid, and has described the composition being excellent in production stability, mechanical properties, molding appearance, weld performance, and lightness. JP2009155418A (PTL 4) has proposed a polyacetal resin composition including a polyacetal resin, a metallic pigment, and a specified liquid additive, and has described the composition not only being excellent in extrusion properties, and retention stability and appearance properties in molding, but also being reduced in the content of an organic solvent and imparting a metallic appearance. WO2013/49541 (PTL 5) has disclosed a polymer composition including a polyacetal resin, a metal pigment, and an ultraviolet stabilizer, in which the metal pigment and the ultraviolet stabilizer are dispersed in sufficient amounts for imparting certain or higher glossiness to an outer surface of a molded product to be obtained.